Effects of polyethylene glycol-grafted phospholipid on the anionic magnetite nanoparticles-induced deformation and poration in giant lipid vesicles

Abstract

The hydrophilic polymer polyethylene glycol-grafted phospholipid has been used extensively in the study of artificial vesicles, nanomedicine, and antimicrobial peptides/proteins. In this research, the effects of 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine-N- [methoxy (polyethylene glycol)-2000] (abbreviated PEG-DOPE) on the deformation and poration of giant unilamellar vesicles (GUVs)-induced by anionic magnetite nanoparticles (NPs) have been investigated. For this, the size of the NPs used was 18 nm, and their concentration in the physiological solution was 2.00 μg/mL. GUVs were prepared using the natural swelling method comprising 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and PEG-DOPE. The mole% of PEG-DOPE in the membranes were 0, 2, and 5%. The degree of deformation of the GUVs was quantified by the parameter compactness (Com), which is 1.0 for the spherical-shaped GUVs. The value of Com increases with time during the interactions of NPs with GUVs for any concentration of PEG-DOPE, but the rate of increase is significantly influenced by the PEG-DOPE concentration in the membranes. The average compactness increases with the increase of PEG-DOPE%, and after 60 min of NPs interaction, the values of average compactness for 0, 2, and 5% PEG-DOPE were 1.19 ± 0.02, 1.26 ± 0.03 and 1.35 ± 0.05, respectively. The fraction of deformation (Frd) also increased with the increase of PEG-DOPE%, and at 60 min, the values of Frd for 0 and 5% PEG-DOPE were 0.47 ± 0.02 and 0.63 ± 0.02, respectively. The fraction of poration (Frp) increased with the increase of PEG-DOPE, and at 60 min, the values of Frp for 0 and 5% PEG-DOPE were 0.25 ± 0.02 and 0.48 ± 0.02, respectively. Hence, the presence of PEG-grafted phospholipid in the membranes greatly enhances the anionic magnetite NPs-induced deformation and poration of giant vesicles.

A review on the measurement of the bending rigidity of lipid membranes

“…The bending rigidity was found to increase and eventually saturate with increasing mole fraction of polyethylene glycol (PEG)-grafted lipid. 172–174 Also, the rise in bending rigidity was more pronounced, and the saturation values for low mol% of PEG vesicles were significantly higher for GUVs synthesized with longer PEG chain lengths. Besides, bending rigidity with various compositions in the presence of the polysaccharide chitosan was obtained through fluctuation analyses.…”

Determination of pore edge tension from the kinetics of rupture of giant unilamellar vesicles using the Arrhenius equation: effects of sugar concentration, surface charge and cholesterol

“…If the pore fails to close, rupturing of cells or vesicles occurs. 4,5 It has been investigated that a pore can be induced in the membrane due to various reasons, such as applying external force using micropipettes, 6 electric field, 7–10 optical illumination, 11 binding of antimicrobial peptides, 12,13 pore-forming toxins, 14 nanoparticles, 15,16 etc. Among the known factors influencing pore formation and growth, pore edge tension, Γ (sometimes referred to as line tension), plays an important role in pore dynamics of the lipid bilayers.…”